CN102712862A

CN102712862A - Polyolester lubricants for refrigeration systems

Info

Publication number: CN102712862A
Application number: CN2010800448732A
Authority: CN
Inventors: D·卡尔; J·赫特尔; E·赫塞尔; R·凯利; R·乌雷格
Original assignee: Crompton Corp
Current assignee: Lanxess Solutions US Inc
Priority date: 2009-10-07
Filing date: 2010-09-16
Publication date: 2012-10-03
Anticipated expiration: 2030-09-16
Also published as: WO2011043905A1; US8518295B2; IN2012DN02250A; EP2486112A1; BR112012007422A2; AU2010303861A1; CN102712862B; AU2010303861B2; JP2013507483A; JP5433790B2; US20110079749A1; EP2486112B1

Abstract

A polyol ester suitable for use as a lubricant or a lubricant base stock has a kinematic viscosity at 40 DEG C greater than or equal to 200 cSt and a viscosity index of greater than or equal to 100. The ester comprises the reaction product of (a) a polyhydric alcohol component comprising at least 50 mole % of penterythritol, and (b) a carboxylic acid component comprising: (i) at least one linear or branched monocarboxylic acid having 2 to 7 carbon atoms; (ii) at least one branched monocarboxylic acid having 8 to 15 carbon atoms; and (iii) at least one polycarboxylic acid having 2 to 8 carbon atoms; wherein the ratio of the number of acid groups derived from the monocarboxylic acid(s) (i) to the number of acid groups derived from the monocarboxylic acid(s) (ii) is between about 0.9 and about 1.1 and the number of acid groups derived from the polycarboxylic acid(s) (iii) is between about 15 % and about 25 % of the total number of acid groups derived from the carboxylic acids (i), (ii) and (iii).

Description

The lubricant that is used for refrigeration system

Technical field

The present invention relates to polyol ester lubricant and they in the purposes that is used for freezing with the working fluid of air conditioning system.

Background of invention

Well-known in the art the lubricant of polyol ester (POE) as the displaced type refrigeration system.Commercial POE commonly used stems from the reaction of polyvalent alcohol (alcohol that contains 2 or more a plurality of OH groups) and monofunctional carboxylic.The polyol ester of this kind " simply " or " routine " is particularly suitable for utilizing the for example system of R-134a and associated molecule of fluoroether refrigerant (HFC), but this is with other lubricant for example MO, poly-alpha-olefin or the alkylaromatic polarity of comparing them provide and the improved compatibility of said refrigeration agent.An instance of this kind polyol ester lubricant is disclosed in U.S. Patent number 6,221, in 272.

The physical property of simple polyol ester mainly is derived from the structure of said acid constituents.Because there is various commercially available carboxylic acid, so simple polyol ester can have the specific physical of optimizing for specific refrigeration system application through design.But, optimize in the time of to all desired properties to exist and limit for simple polyol ester.For example; Optimized lubricant will be a kind of like this lubricant; Be but that it has high compatibility guaranteeing the good transportation of lubricant in other cryogenic assembly of vaporizer and refrigeration cycle with refrigeration agent at low temperatures, but in compressor under the high temperature and pressure refrigeration agent in lubricant, have the solvability of very low or difference so that the lubricant viscosity that refrigeration agent causes reduces minimizes.

The lubricant viscosity that under high temperature and pressure, is caused by refrigeration agent reduces the hydrokinetics lubricity that reduces lubricant significantly.In addition, through using oilness and the load bearing capacity that has improved the polyol ester lubricant than long-chain linear acid rather than than short chain and/or branched-alkyl.But concerning but just in time opposite with the compatibility of HFC or fluorohydrocarbon refrigeration agent but (that is, but branching and/or improve compatibility) than short chain acyl.But so exist to require to optimize simultaneously lubricant and refrigeration agent at low temperatures the compatibility characteristic and under high temperature and pressure the deliquescent careful balance of refrigeration agent in lubricant, also keep the oilness of lubricant and the optimum balance of load bearing capacity simultaneously.In addition, along with refrigeration system manufacturers begins to tend to more low viscous lubricant to improve energy efficiency, will become more remarkable to the oilness of lubricant and the negative impact of load bearing capacity.

Improving the oilness of refrigeration lubricant and a kind of mechanism of load bearing capacity is to comprise wear-resistant/extreme-pressure additive.Yet examples of such additives possibly be undesirable because they at low temperatures (like what in vaporizer, run into) from lubricant, precipitate separate out or under very high temperature (like what in compressor, experience) resolve into undissolved by product.Additive this kind from lubricant " separated out " (drop out) possibly cause the settling on the coolant system expansion gear (thermo expansion valve, kapillary or needle valve) usually; Or the obstruction fully of said expansion gear, this causes the refrigeration performance reduction of system or the complete failure of system.In addition, for the compressor with internal engine, the circuit coating of using on additive and the mover (wire coating) has the possibility that adverse effect takes place, and this causes the dissolving of circuit coating in this system and finally is deposited on the expansion gear assembly.

Therefore, still need a kind of like this refrigeration lubricant, but promptly it has high compatibility with refrigeration agent in wide operating temperature range, also under the situation of not using additive, keeps enough oilnesies and load bearing capacity simultaneously; Protection and the other energy efficiency of improving refrigeration system to the cooling assembly wearing and tearing are provided.

Solving a kind of of this needs possibly mode be to adopt complicated polyol ester, promptly through making the alcohol and the polycarboxylic acid (fusion has one or more monocarboxylic acids usually) that contain at least two-OH group react the ester that forms.Therefore, because their additional sour site, polyprotonic acid provides the possibility of the performance of regulating the gained ester demands of different to satisfy optimized lubricant.

For example, USP 5,096; 606 disclose the refrigeration oil compsns, and it comprises (1) and is selected from 1,1; 1,2-fluoroethane, pentafluoride ethane, 1,1; 1-HFC-143a and 1, the fluoroethane of 1-C2H4F2 C2H4F2 is the ester cpds by the reaction product of following component acquisition with (2): (a) have the aliphatic polyol of 1-6 primary hydroxyl, (b) have the radical of saturated aliphatic straight chain or the branching monocarboxylic acid of 2-9 carbon atom; Or derivatives thereof and the radical of saturated aliphatic straight chain or the branching di-carboxylic acid that (e) have 2-10 carbon atom, or derivatives thereof, said ester cpds have 100 ℃ of kinematic viscosity of 1-100cst.

In addition, USP 5,551; 524 disclose the lubricated method that contains the motorcar air conditioner of refrigeration agent heat exchange fluid (its molecule that is contained at least one chlorine atom by per molecule constitutes with the mineral oil lubricant that is dissolved in wherein) at first; Wherein this refrigeration agent heat exchange fluid and mineral oil lubricant have replaced with the working fluid that machine refrigerant heat exchange fluid and lubricant or lubricant base are arranged that comprises no chlorine, fluoro-containing group, and said method is characterised in that this lubricant or lubricant base are that viscosity is 40 ℃ of liquid of about 45 to 220cSt down; Itself and 1; 1,1, the 2-Tetrafluoroethane is miscible under being low to moderate-55 ℃ at least; And form by the mixture of polyol ester molecule basically; Wherein at least 92% alcohol moiety is derived from PE, and at least 92% acyl group is selected from the monobasic of all straight chains and branching and the acyl group of di-carboxylic acid (having 4-12 carbon atom separately), and said alcohol moiety and acyl group also are subject to when selecting: (a) in the mixture altogether at least 5% acyl group be i-C ₅The acyl group of acid; (b) contain in the mixture in acyl group % and the mixture of 8 or more carbon atoms simultaneously for branching and the ratio that contains the acyl group % that is no more than 6 carbon atoms and be not more than 1.56; (c) the acyl group % that contains at least 9 carbon atoms whether (no matter branching) in the mixture is not more than 81; (d) being no more than 2% acyl group in this ester mixture is a part that has the acid molecule of two above carboxyls separately; (e) amount at least 20% acyl group has at least two alkyl substituent side chains from each acid molecule C in this mixture ₉And C ₈Acid; (f) in this ester mixture at least 4.6% but be no more than 13% acyl group from hexanodioic acid.

In addition; USP 5; 853; 609 disclose and a kind ofly between approximately-40 ℃ to about 71 ℃, have kept monophasic refrigeration agent working fluid; The compsn of heat-transfer fluid that said working fluid comprises free from chloride fluoro-containing group basically and the material that is suitable for serving as lubricant base, said heat-transfer fluid comprises pentafluoride ethane, 1,1-C2H4F2 C2H4F2,1; 1; At least a in 1-HFC-143a and the Tetrafluoroethane, said compsn be under 40 ℃, have about 44 centistokes(cst)s of about 22.5-(cSt) viscosity liquid and form by the mixture of polyol ester molecule basically, wherein at least 85% of the monoprotic acid molecule in acid mixture by the molecular composition that has 5 or 9 carbon atoms separately; About at least 92% of alcohol structure division is selected from the acyl group that is selected from all straight chains that have 4-12 carbon atom separately and side chain monobasic and di-carboxylic acid derived from about at least 92% of the pure structure division of tetramethylolmethane (PE) and Dipentaerythritol (DPE) and acyl group, and said pure structure division and acyl group are further selected according to following restricted condition: (a) about at least altogether 7% of the acyl group in the said mixture is i-C ₅The acyl group of acid; (b) in the said mixture contain 8 or the percentage of more a plurality of carbon atom and nonbranched acyl group and said mixture in not only branching but also the ratio that contains the percentage of the acyl group that is not more than 6 carbon atoms be not more than about 1.56; (c) percentage of the acyl group that contains at least 9 carbon atoms in the said mixture whether (no matter branching) is not more than about 81; (d) being not more than of the acyl group in the said ester mixture about 2% belongs to the acid molecule that has separately more than two carboxyls; (e) at least 60% of the monoprotic acid molecule in the said acid mixture by having the molecular composition of 10 carbon atoms at the most separately; (f) about at least altogether 20% of the acid molecule in the said mixture is one of tri-methyl hexanoic acid; About at least 85% of pure structure division in the said ester is those of PE; And being not more than of the acyl group in the said ester mixture about 7.5% is binary.

For some application, particularly when being used for the working fluid of heavy refrigeration and air-conditioning system, importantly this polyol ester has high kinematic viscosity, promptly under 40 ℃ greater than 200cSt.

U.S.'s publication application 2005/0049153 discloses the high viscosity lubricants compsn that comprises the complicated pluralism alcohol ester, and it has: (a) polyfunctional alcohol's residue; (b) has the saturated or unsaturated dicarboxylic acid residue of about 22 carbon atoms of about 9-.All complicated pluralism alcohol esters for example have 40 ℃ of viscosity above 200cSt.But, need long chain dicarboxylic acid to realize these high viscosity values, there are limited compatibility in itself and hydrogen fluorohydrocarbon working fluid, and have the limited potentiality as refrigeration lubricant thus.

The approach more commonly used that is used to prepare the complicated polyol ester of HV is to use the polyvalent alcohol precursor, particularly Dipentaerythritol (DiPE) with higher hydroxy functionality.But DiPE also is expensive and its supply depends primarily on the demand of monopentaerythritol (PE), because DiPE is the part by product that PE makes.Some the time, the PE demand reduces and the supply of DiPE is very limited or do not exist.There is demand thus, comprises the HV ester, and needn't use this costliness and composition that may not obtain for the discrimination method of composition that reproduces the polyol ester that derives from DiPE usually and performance.

According to the present invention; Have now found that; Can be through using linear and branching monocarboxylic acid and the polycarboxylic particular combination of short chain, by make the complicated pluralism alcohol ester that has greater than the consistency of 40 ℃ of kinematic viscosity, high viscosity index (HVI) and acceptable and the fluoroether refrigerant of 200cSt as the raw-material PE of polyvalent alcohol.

Summary of the invention

On the one hand; The invention reside in the polyol ester that is suitable as lubricant or lubricant base; Said ester has more than or equal to 40 ℃ of kinematic viscosity of 200cSt with more than or equal to 100 viscosity index; Said ester comprises the reaction product of following component: (a) comprise the polyhydroxy-alcohol component of 50mol% tetramethylolmethane at least and (b) carboxyl acid component, said carboxyl acid component comprises:

(i) at least a linearity or branching monocarboxylic acid with 2-7 carbon atom;

(ii) at least a branching monocarboxylic acid with 8-15 carbon atom; With

(iii) at least a poly carboxylic acid with 2-8 carbon atom;

Be 0.9 to 1.1 with ratio wherein derived from monocarboxylic acid acid groups number (ii) derived from the acid groups number of monocarboxylic acid (i), and derived from poly carboxylic acid acid groups number (iii) be derived from carboxylic acid (i), (ii) and acid groups overall number (iii) 15% to 25%.

Advantageously, this polyhydroxy-alcohol component comprise at least 90mol%, like the tetramethylolmethane of 95mol% at least.

Advantageously, said at least a linearity or branching monocarboxylic acid (i) have 5-7 carbon atom, and comprise isovaleric acid in one embodiment.

Advantageously, said at least a branching monocarboxylic acid (ii) has 8-12 carbon atom, and comprises different n-nonanoic acid in one embodiment.

Advantageously, said at least a poly carboxylic acid (iii) has 4-7 carbon atom, and comprises hexanodioic acid in one embodiment.

Advantageously, be 0.9 to 0.95 derived from the acid groups number of monocarboxylic acid (i) with ratio derived from monocarboxylic acid acid groups number (ii), according to appointment 0.93.

Advantageously, derived from poly carboxylic acid acid groups number (iii) be derived from carboxylic acid (i), (ii) and acid groups overall number (iii) 19% to 21%.

On the other hand, the invention reside in the working fluid that comprises polyol ester described in halogenate hydrocarbon refrigerant and this paper.

Description of drawings

Fig. 1 is when described in embodiment 2, in miniature-traction machine test, testing, for embodiment 1 and comparative example's 1 lubricant, at 80 ℃ of temperature and 30N the load increase of The friction coefficient entrainment velocity and the graphic representation of variation down.

Fig. 2 is when described in embodiment 2, in miniature-traction machine test, testing, for embodiment 1 and comparative example's 1 lubricant, at 120 ℃ of temperature and 30N the load increase of The friction coefficient entrainment velocity and the graphic representation of variation down.

Fig. 3 is when described in embodiment 2, in miniature-traction machine test, testing, for embodiment 1 and comparative example's 1 lubricant, at 135 ℃ of temperature and 30N the load increase of The friction coefficient entrainment velocity and the graphic representation of variation down.

Fig. 4 is when described in embodiment 2, in miniature-traction machine test, testing; For embodiment 1 and comparative example's 1 lubricant, 80 ℃, 120 ℃ and 135 ℃ of temperature and 30N load down frictional coefficient with respect to the graphic representation of slides/rolls ratio variation.

Embodiment

Described among this paper and had more than or equal to 40 ℃ of kinematic viscosity of 200cSt with more than or equal to the polyol ester of 100 viscosity index.Typically, this polyol ester has 40 ℃ of kinematic viscosity of about 220cSt and 100 ℃ of kinematic viscosity of about 20cSt, and about 100 to about 110 viscosity index.This polyol ester as having wide compatibility scope among the R-134a, makes it desirably as lubricant or lubricant base in the working fluid of heavy duty industrial refrigeration and air-conditioning system in addition at fluoroether refrigerant.

Polyol ester of the present invention comprises following reaction product: (a) comprise 50mol% at least, typically at least 90mol%, like the polyhydroxy-alcohol component of 95mol% even 100mol% tetramethylolmethane at least and (b) comprise the mixture of carboxylic acids of following material:

(i) at least a linearity or branching monocarboxylic acid with 2-7 carbon atom;

(ii) at least a branching monocarboxylic acid with 8-15 carbon atom; With

(iii) at least a poly carboxylic acid with 2-8 carbon atom.

This at least a linearity or branching monocarboxylic acid (i) have 5-7 carbon atom usually, and advantageously are selected from positive valeric acid, isovaleric acid, n-caproic acid, isocaproic acid, positive enanthic acid and isoamyl acetic acid.In one embodiment, this at least a linearity or branching monocarboxylic acid (i) comprise isovaleric acid.

This at least a branching monocarboxylic acid (ii) has 8-12 carbon atom usually, and in said a kind of embodiment, comprises different n-nonanoic acid (3,5,5 Trimethylhexanoic acid).

Derived from being about 0.9 to 1.1 derived from the ratio of monocarboxylic acid acid groups number (ii) in the acid groups number of monocarboxylic acid (i) and the said mixture, and typically be about 0.9 in the mixture of carboxylic acids (b), according to appointment 0.93 to about 0.95.

This at least a poly carboxylic acid (iii) has 4-7 carbon atom, and in said a kind of embodiment, comprises hexanodioic acid.

Derived from poly carboxylic acid acid groups number (iii) be in the mixture of carboxylic acids (b) the acid groups overall number about 15% to about 25%, typically be about 19% to about 21%.

Polyol ester of the present invention can react with single stage method or two-step approach and prepare.

In single stage method; Polyvalent alcohol, polyprotonic acid and the unit acid of whole consumptions or acid mixture are packed into when the reaction beginning in the reaction vessel; Regulate polyvalent alcohol and sour relative consumption in the charging, arrive about total hydroxyl of 1.3, preferably about 0.95 to about 1.15 and more preferably about 1.0 to about 1.1 to provide about 0.9: carboxyl molar equivalent ratio.

In two-step approach; Polyhydroxy-alcohol (feeding in raw material so that 1.0 molar equivalent hydroxyls to be provided) is packed in the reaction vessel with the sour charging of the poly carboxylic acid of the expectation that comprises whole consumptions and a part of monocarboxylic acid in the first step; Provide thus and amount to about 0.8 acid, the acid of 0.87 molar equivalent according to appointment to about 0.9 molar equivalent.In the first step, use monocarboxylic acid in shortage to help to guarantee that all dicarboxylicacid are by esterification.Subsequently charging is heated to the end reaction temperature, and proceed the first step reactions step up to the acid number of this charging less than 5, more preferably less than 1.In case realized the target acid number in the first step; Just pack remaining monocarboxylic acid into reaction vessel so that reach numerical value about 0.9 to about 1.3, preferably about 0.95 to about 1.15 and more preferably about 1.0 to about 1.1 from the two total sour molar equivalent of diprotic acid and monoprotic acid.

No matter carry out, in the reaction vessel that mechanical stirrer, enlightening case-Stark water trap and vertical water cooled condenser, thermopair/heating jacket/temperature controller and nitrogen purging are housed, carry out usually with single stage method or two-step approach.Randomly, in reaction mixture, add catalyzer such as stannous oxalate.Under slight nitrogen purge, charging is heated to 220-260 ℃ of end reaction temperature, in enlightening case-Stark water trap, collects reaction water during this period and acid is turned back in the reactor drum.Last under reduced pressure from reaction mixture, remove excessive arbitrarily acid to less than 10 OH value with less than 0.10 acid number.

The ester of gained can need not to be further purified just and use, perhaps can adopt conventional art like distillation, adopt acid scavenger to handle to remove acid traces, to adopt moisture scavenger to handle with dry-off moisture and/or filter to be further purified to improve purity.

Polyol ester of the present invention be intended to especially as the refrigeration and air-conditioning system with the lubricant in the working fluid; Wherein with this ester and heat exchange fluid, normally fluorine-containing organic cpds such as hydrogen fluorohydrocarbon or fluorohydrocarbon; The mixture of two or more hydrogen fluorohydrocarbons or fluorohydrocarbon, the combined hybrid of perhaps any aforementioned substances and hydro carbons.The fluorohydrocarbon that is fit to and the limiting examples of hydrogen fluorocarbon compound comprise tetrafluoro-methane (R-14), methylene fluoride (R-32), 1,1,1; 2-Tetrafluoroethane (R-134a), 1; 1,2,2-Tetrafluoroethane (R-134), pentafluoride ethane (R-125), 1; 1,1-HFC-143a (R-143a) and tetrafluoeopropene (R-1234yf).The limiting examples of the mixture of hydrogen fluorohydrocarbon, fluorohydrocarbon and/or hydrocarbon comprise R-404A (1,1,1-HFC-143a, 1,1; 1, the mixture of 2-Tetrafluoroethane and pentafluoride ethane), R-410A (mixture of 50wt% methylene fluoride and 50wt% pentafluoride ethane), R-410B (mixture of 45wt% methylene fluoride and 55wt% pentafluoride ethane), R-417A (1,1; 1, the mixture of 2-Tetrafluoroethane, pentafluoride ethane and normal butane), R-422D (1,1; 1, the mixture of 2-Tetrafluoroethane, pentafluoride ethane and Trimethylmethane), R-427A (methylene fluoride, pentafluoride ethane, 1,1; 1-HFC-143a and 1,1,1; The mixture of 2-Tetrafluoroethane) and R-507 (pentafluoride ethane and 1,1, the mixture of 1-HFC-143a).

Polyol ester of the present invention can also with non-HFC refrigeration agent for example R-22 (chlorodifluoromethane), dimethyl ether, hydrocarbon coolant for example Trimethylmethane, carbonic acid gas and ammonia uses together.Comprehensive inventory of the refrigeration agent that other is useful can be referring to European publication application EP 1985681A, and the document is incorporated herein by reference in full.

Contain above-mentioned polyol ester as the working fluid of base oil can further contain MO and/or synthetic oil for example poly-alpha-olefin, korenyl, except that above-mentioned those ester, polyethers, polyvingl ether, PFPE, SULPHOSUCCINIC ACID ESTER and/or their mixtures ester.

In addition, can in this working fluid, add the traditional lubrication agent addition agent, for example inhibitor, extreme-pressure additive, wear preventive additive, friction reduce additive, skimmer, short infusion, metal passivator, acid scavenger etc.

The instance of operable inhibitor comprises phenol antioxidant for example 2,6-two-tertiary butyl-4-methylphenol and 4,4 '-methylene-bis (2,6-two-tert.-butyl phenol); Amine antioxidants is p for example, p-dioctyl phenyl amine, single octyldiphenylamine, thiodiphenylamine, 3,7-dioctyl thiodiphenylamine, phenyl-1-naphthylamine, phenyl-2-naphthylamines, alkyl phenyl-naphthalidine and alkyl phenyl-2-naphthylamines; Sulphur-containing antioxidant is alkyl disulfide, thiodipropionate and benzothiazole for example; With zinc dialkyl dithiophosphate and diaryl zinc dithiophosphate.

The instance that operable extreme-pressure additive, wear preventive additive, friction reduce additive comprises zn cpds for example zinc dialkyl dithiophosphate and diaryl zinc dithiophosphate; Sulphur compound for example thiodipropionate, dialkyl sulfide, dibenzyl sulfide, dialkyl polysulfide, alkyl sulfhydryl, dibenzothiophene and 2,2 '-dithio two (benzothiazole); The ashless wear preventive additive of sulphur/nitrogen is dialkyl group Vanchem DMTD and methylene-bis (N, N-dialkyl dithio amino formate) for example; Phosphorus compound is for example Tritolyl Phosphate and trialkylphosphate of triaryl phosphate for example; Di(2-ethylhexyl)phosphate alkyl or diaryl ester; Tricresyl phosphite alkyl or triaryl ester; The amine salt of alkyl and dialkyl phosphate is the dodecyl amine salt of dimethyl-SULPHOSUCCINIC ACID ESTER for example; Phosphorous acid dialkyl group or diaryl ester; Phosphorous acid monoalkyl or single aryl ester; Fluorine cpd are perfluoroalkyl polyethers, trifluorochloroethylene polymkeric substance and graphite fluorochemical for example; The for example fatty acid modified silicone of silicon compound; Molybdenumdisulphide, graphite etc.The instance of organic friction improver comprises long-chain fat amine and glyceryl ester.

The instance of operable skimmer and short infusion comprises for example dimethyl polysiloxane and organosilicon acid esters silicic acid diethyl ester for example of silicone oil.The instance of operable metal passivator comprises benzotriazole, tolyl-triazole, rubican, quinizarin and mercaptobenzothiazole.In addition, can add epoxy compounds for example phenylglycidyl ether, alkyl glycidyl base ether, alkyl glycidyl base ester, epoxy group(ing) stearate and epoxidized vegetable oil, organo-tin compound and boron cpd as acid scavenger or stablizer.

The instance of dehumidizier comprises alkyl orthoformate for example trimethyl orthoformate and triethyl orthoformate, ketal for example 1,3-dioxolane and amino ketal for example 2,2-Er Wan Ji oxazolidine.

The working fluid that comprises ester of the present invention and refrigeration agent can be used for various refrigeration and transfer of heat energy application; But be intended to be used for the industrial air-conditioning unit of using in factory, office building, residential building and emporium especially and be used for the emporium and large-scale freezing unit that ice rink is used.

The type that can be used for the compressor of above-mentioned application can be divided into two big types; Positive displacement (positive displacement) and power (dynamic) compressor.Positive-displacement compressor is through improving refrigerant vapor via the volume that puts on the merit reduction pressure space on the compressor means.Positive-displacement compressor comprises the compressor of the many patterns in the current use, for example moves back and forth, rotates (rolling piston, rotary vane, single screw rod, twin screw) and track (rolling or swing) compressor.Power compressor then changes into the pressure rising with this energy and improves refrigerant vapor through the continuous transfer of kinetic energy from the revolving meber to the steam.Turbo-compressor is based on these principle operations.The design and running details that is used for these compressors of refrigeration application can be referring to the 2008ASHRAE handbook, HVAC system and equipment, the 37th chapter; The content of the document is through introducing income in full.

To the present invention more specifically be described with reference to following indefiniteness embodiment and accompanying drawing at present.

Embodiment 1

With monopentaerythritol (136.2g, 1.0 moles; 4.0 the hydroxyl of molar equivalent) together with 156.3g (1.53mol) isovaleric acid, the positive enanthic acid of 2.6g (0.02mol), the different n-nonanoic acid (3 of 261.1g (1.65mol); 5; The 5-tri-methyl hexanoic acid), 58.5g (0.40mol, 0.8 equivalent H+) hexanodioic acid and adding of 0.2 gram stannous oxalate catalyzer are equipped with the round-bottomed flask of mechanical stirrer, enlightening case-Stark water trap and vertical water-cooled condenser, thermopair/heating mantles/temperature controller and nitrogen purging.Therefore, aspect the acid constituents of this reaction mixture, the 38.25mol% of acid groups stems from isovaleric acid, and 0.5mol% stems from enanthic acid, and 41.25% stems from different n-nonanoic acid, and 20mol% stems from hexanodioic acid.

This charging is heated to about 227 ℃-232 ℃ end reaction temperature.In enlightening case-Stark water trap, collect reaction water, simultaneously any distillatory acid is sent back to reactor drum.Apply vacuum as required to keep reaction.When hydroxyl value being reduced to enough low level (maximum 5.0mg KOH/gm), remove excess acid through vacuum distilling.With in the acid scavenger and residual acidity.The eater base stocks of dry gained and filtration under nitrogen purging.Performance through filtering base-material is summarised in the table 1, can find out that from this table 1 said eater base stocks has the 40 ℃ of kinematic viscosity of 204.3cSt and 108 viscosity index.

The comparative example 1

Comparative example 1 is ISO 220 polyol esters that are purchased, and it can obtain from Chemtura Corporation with trade(brand)name Hatco 3316.It is derived from the reaction of Dipentaerythritol with the mixture of positive valeric acid and different n-nonanoic acid.The performance of commerical prod also is summarized in the table 1.

The data that from table 1, provide can be found out; The lubricant that the lubricant of embodiment 1 is compared comparative example 1 has higher viscosity index and lower pour point, still has simultaneously good compatibility (be defined as this moment less than-20 ℃ under miscible with 10 volume percent and R-134a).

Comparative example 2-11

Use generalized polyvalent alcohol, C in the table 2 and 3 ₅-C ₉The different mixtures of monocarboxylic acid and hexanodioic acid, the process of repetition embodiment 1.The physicals through filtering base-material of gained also is summarized in the table 2.

To find out that from table 2 comparative example 1 and 2 product use the combination of valeric acid/different n-nonanoic acid or isovaleric acid/positive enanthic acid/different n-nonanoic acid respectively, (DiPE) makes by Dipentaerythritol.These products have the restriction of low temperature compatibility in less than-20 ℃ R-134a, but have low viscosity index.

To find out also that from table 2 product of comparative example 3-6 uses the monoprotic acid mixture of pure monopentaerythritol or technical grade pentaerythritol (containing the 10wt% Dipentaerythritol) and valeric acid/different n-nonanoic acid and prepares as the hexanodioic acid of diacid.These products or have 40 ℃ of kinematic viscosity, or the low temperature compatibility restriction under greater than-20 ℃ in R-134a less than 200cSt, or the two all exists.

But comparative example 7-11 is to use the starting material identical with embodiment 1 product example of relative consumption as shown in table 3, and it can not provide 40 ℃ of kinematic viscosity of 200cSt at least and in R-134a under the 10 volume percent lubricants＜-20 ℃ the low temperature compatibility limit.

Embodiment 2: lubricity test

Use can be estimated the oilness of embodiment 1 and comparative example's 1 lubricant from the miniature tractor (MTM) that PCS Instruments is purchased acquisition.The solid geometry of screw has been measured the lubricated/frictional behaviour of lubricant on this test employing dish through two kinds of different technologies.

In first kind of pattern operation, measure the oilness of lubricant down in full fluid film condition (hydrodynamic lubrication).The speed of simultaneously crooked (ramped) ball of the slip with 50%-rolling ratio and dish, and the variation (Stribeck curve) of under constant load and temperature, measuring the The friction coefficient entrainment velocity.This point means that ball warp is often moved with 50% rotating disk speed when the speed of bending dish.Along with the speed raising of dish and ball, because lubricant exists pressure to build up to the motion of metal-metal contact side at the leading portion of roll/slide contact.Become enough fast and pressure becomes and is enough to cause the entrainment of lubricant between ball and dish contact at some point velocities.This moment, this system was under the hydrodynamic lubrication, meaned that lubricated integrity by the film between ball and the dish controls.Lower frictional coefficient representes to have the lubricant of better lubricity under high entrainment velocity.

In second kind of pattern operation, all measuring oilness (border, hybrid films, elastic fluid power and hydrodynamic force) in the lubricating status scope.In this test, under constant load and temperature, measure frictional coefficient (traction curve) with different slides/rolls ratios (promptly with different rates rotating disk respect to one another and ball).

For two kinds of pattern operations, typically under several kinds of different fixed temperature, make an experiment: 80,120 and 135 ℃ and 30N load under this situation.Frictional coefficient is the direct tolerance of lubricant oilness, and frictional coefficient is low more, and the lubricant oilness is high more.Emphasis is pointed out that this test is significant for the lubricant of more suitable ISO viscosity grade only.The result provides in Fig. 1-4.

Stribeck curved measurement shown in Fig. 1-3 under 80 ℃, 120 ℃ and 135 ℃ has confirmed that lubricant of the present invention compares than lubricant and often has lower frictional coefficient.Frictional coefficient result shown in Fig. 4 has confirmed that lubricant that lubricant of the present invention (embodiment 1) compares comparative example 1 is lower to frictional force under the fixed temperature.

Though invention has been described and illustrate with reference to specific embodiment, those skilled in the art will recognize that the present invention is applicable to not necessarily illustrational in this article variant.Therefore, then should only confirm true scope of the present invention according to appended claims.

Claims

1. be suitable as the polyol ester of lubricant or lubricant base; Said ester has more than or equal to 40 ℃ of kinematic viscosity of 200cSt with more than or equal to 100 viscosity index; And said ester comprises the reaction product of following component: (a) comprise the polyhydroxy-alcohol component of 50mol% tetramethylolmethane at least; (b) carboxyl acid component, said carboxyl acid component comprises:

(i) at least a linearity or branching monocarboxylic acid with 2-7 carbon atom;

(ii) at least a branching monocarboxylic acid with 8-15 carbon atom; With

(iii) at least a poly carboxylic acid with 2-8 carbon atom;

2. the ester of claim 1, wherein this polyhydroxy-alcohol component comprises at least 90mol% and the tetramethylolmethane of 95mol% at least preferably.

3. claim 1 or 2 ester, wherein said at least a linearity or branching monocarboxylic acid (i) have 5-7 carbon atom.

4. the ester of arbitrary aforementioned claim, wherein said at least a linearity or branching monocarboxylic acid (i) are selected from positive valeric acid, isovaleric acid, n-caproic acid, isocaproic acid, positive enanthic acid and isoamyl acetic acid.

5. the ester of arbitrary aforementioned claim, wherein said at least a branching monocarboxylic acid (ii) has 8-12 carbon atom.

6. the ester of arbitrary aforementioned claim, wherein said at least a branching monocarboxylic acid (ii) comprises different n-nonanoic acid (3,5,5 Trimethylhexanoic acid).

7. the ester of arbitrary aforementioned claim, wherein said at least a poly carboxylic acid (iii) has 4-7 carbon atom.

8. the ester of arbitrary aforementioned claim, wherein at least a poly carboxylic acid (iii) comprises hexanodioic acid.

9. the ester of arbitrary aforementioned claim is 0.9 to 0.95 derived from the acid groups number of monocarboxylic acid (i) with ratio derived from monocarboxylic acid acid groups number (ii) wherein, and is preferably about 0.93.

10. the ester of arbitrary aforementioned claim, wherein derived from poly carboxylic acid acid groups number (iii) be derived from carboxylic acid (i), (ii) and acid groups overall number (iii) 19% to 21%.

11. lubricant blend, the polyol ester that comprises arbitrary aforementioned claim has the mixture of the polyol ester of the kinematic viscosity that is different from the said polyol ester of at first mentioning with other.

12. comprise the working fluid of each polyol ester among halogenate hydrocarbon refrigerant and the claim 1-10.

13. the working fluid of claim 12, wherein this refrigeration agent is hydrogen fluorohydrocarbon, fluorohydrocarbon or its mixture.